Condition responsive device



Filed Feb. 24. 1939 Inventor: William D. Cockrell, by Wad/1.252 4Attorney.

April 22, 1941. w. D. COC KRELL CONDITION RESPONSIVE DEVICE iii PatentedApr. 22, 1941 CONDITION BESPONSIVE DEVICE William D. Cockrell,Schenectady, N. Y., assignor to General Electric Company, a corporationof New York Application February 24, 1939, Serial No. 258,348

9 Claims.

This invention relates to condition responsive devices and moreparticularly to devices for controlling an electrical circuit inresponse to a predetermined rate of fluid flow through a conduitalthough it is not limited thereto necessarily.

It is an object of this invention to provide a new and improvedcondition responsive device comprising a simple, compact structurehaving a minimum number of parts.

For a consideration of what I believe to be novel and my invention,attention is directed to the following description and the claimsappended thereto taken in connection with the accompanying drawing.

In the drawing, Fig. 1 is a perspective view of a fluid flow responsivedevice constructed in accordance with one form of my invention; Fig. 2is a longitudinal view, partly in section, of the device illustrated inFig. 1; and Fig. 3 is a transverse view along line 33 of Fig. 2.

Referring to the drawing, the device comprises a base portion which isprovided with a fluid passage therethrough having an enlarged portion aI2, as regards the direction of fluid flow therethrough, by means of theport I8. The bellows member I! is in communication with the fluidpassage at the throat l2 by means of the port 19. The bellows whichrespond to the different pressures occurring in the correspondingsections of the Venturi passage are adapted to engage with a suitablypivoted lever for imparting thereto a movement in accordance with thepressure difierential. In the preferred embodiment the lever is in theform of a U -shaped cover plate or housing 20 having downwardlydepending side walls which are pivotally secured to the basesubstantially midway between the spaced apart bellows members by meansof the transversely extending pin 2|. The cover plate, which may befurther provided at its opposite ends with strips 22 and 23 suitablysecured between the side walls, substantially encloses the bellowsmembers and shields themfrom foreign objects likely to come intodamaging contact therewith. The outer ends of the bellows members engagewith the upper portion of the cover plate 20 and rock it about the pin2| in response to a differential in pressure occurring in the portions Hand I2 of the Venturi passage.

The lever or cover plate 20 is adapted for actuating a suitable contactmeans or switch 24 for controlling an electrical circuit (not shown) inaccordance with a condition of fluid flow through the device. A bracket25 suitably secured as by spot welding onto a side wall of the coverplate has an adjustable screw 26 threaded therein for engaging with thepush rod 21 extending from the operating mechanism of the-switch 24. Theswitch may be of any suitable type but is preferably one which issensitive to a relatively small movement of the actuating means. It maybe arranged within a self-contained housing which is secured as byscrews 28 to the base In in an operative relationship with the screw 26.With this arrangement, the switch unit is readily removable forreplacement or repair.

If desired, a suitable spring 29 may be arranged between the uppersurface of the base I0 and the cover plate 20 adjacent the low pressurebellows member l'l so that the cover plate will be actuated only upon apredetermined pressure diiference occurring in the bellows members. Thespring may be selected for the desired pre-- determined characteristicor, obviously, the compression thereof may be adjusted by thearrangement of a suitable adjusting screw between the end of the springand the plate 20. The movement of the plate 20 under the biasing forceof the compression spring 29 may be limited by a suitably arranged stop30 (Fig. 1) while movement of the cover plate in the opposite directionis limited by the switch mechanism engaged by the screw 26.

The pressure differential for a given rate of fluid flow through theVenturi passage may be controlled by means of an adjustable plug 3|threaded into the base and adapted to ivary the constriction of thepassage at the tliroat l2. The adjustable plug is preferably arranged inthe throat slightly ahead of the port 19 for greatest effectiveness.

Having described the principle of operation of my invention togetherwith the apparatus which I now consider to represent the best embodimentthereof, I desire to have it understood that the apparatus shown is onlyillustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A condition responsive device comprising a base, a pair of conditionresponsive bellows secured to said base in spaced apart parallelrelationship, a U-shaped lever forming a housing for said bellows andpivotally secured to said base between said bellows, the ends of saidbellows engaging with said lever and adapted to actuate said lever inaccordance with a differential movement of said bellows, a switch unitremovably secured to said base, and adjustable means secured to saidlever for actuating said switch unit.

2. A condition responsive device comprising a base, a lever pivotedintermediate its ends on said base, contact means operatively associatedwith said lever, and a pair of condition responsive bellows mounted onsaid base in a substantially parallel and spaced apart relationship, one

of said bellows engaging with said lever at one side of the pivotalpoint thereof and the second of said bellows engaging with said lever onthe opposite side of the pivotal point thereof with respect to saidfirst bellows, said lever forming a channel substantially enclosing thebellows.

3. A condition responsive device comprising a base, a pair of conditionresponsive bellows secured to said base in a spaced apart parallelrelationship, a U-shaped cover mounted over said bellows and pivotedupon said base between said bellows, the outer ends of said bellowsengaging with said cover, said cover being adapted to be rocked inaccordance with a differential movement of said ,bellows, and contactmeans operatively associated with said cover.

4. A condition responsive device comprising a base, a pair of conditionresponsive bellows mounted in spaced apart relationship upon said baseand extending parallel with respect to each other, a lever pivoted uponsaid base between said bellows, the lever having end portionssubstantially enclosing and engag ng with the outer ends of said bellowsand adapted to be actuated thereby, and contact means operativelyassociated with said lever.

5. In combination, a Venturi tube, a pair of expansible bellows mountedon said tube in a substantially parallel and spaced apart relationshipand communicating with the high and low pressure regions respectively ofsaid tube, a cover for said bellows engaging with the outer ends thereofpivotally secured to said tube between said bellows, and means actuatedby said cover in response to predetermined differential expansionmovements of said bellows.

6. In combination, a Venturi tube, a pair of protecting and expansiblebellows mounted in a substantially parallel and spaced apartrelationship on said tube and communicating with the high and lowpressure regions thereof, a cover plate substantially surrounding saidexpansible bellows and pivotally secured to said tube between saidbellows, the outer ends of said bellows engaging with said cover plate,and meansadapted to be actuated by said cover plate in response todifferential movements of said bellows.

7. A fluid flow responsive device having a base comprising asubstantially rectangular metal block, a Venturi passage through saidbase comprising an enlarged portion and a throat portion, a pair ofbellows members secured to the upper surface of said base in spacedapart and substantially parallel relationship, one of said bellowscommunicating with the enlarged portion of said passage, the other ofsaid bellows communicating with the throat portion of said passage, acover substantially surrounding said bellows membersand pivotallysecured to said base between said bellows members, the outer ends ofsaid bellows members engaging with said coverand adapted to actuate saidcover in accordance with the difierential expansion movements of saidbellows, and contact means adapted to be actuated by said cover.

8. A fluid flow responsive device comprising a base, a Venturi passagethrough said base having an enlarged portion and a throat portion, apair of bellows members secured on said base in a spaced apart andsubstantially parallel relationship, one of said bellows communicating Iwith the enlarged portion of said passage, the other of said bellowscommunicating with the throat portion of said passage, a housing for thebellows pivoted upon said base and adapted to be actuated in accordancewith diiierential of the pressures occurring in said Venturi passage,means for determining the actuation of said housing, and. adjustablemeans for varying the pressure difference created in said Venturipassage tor a .given rate of fluid flow therethrough.

9. A device responsive to flow or like condition of a fluid comprising abase forming a channel for receiving such fluid-during operation, abellows having one end secured to the base in communication with thechannel, and a housing substantially enclosing the bellows, said housingbeing pivotally held on the base and having a portion engaging the upperend of the bellows whereby the housing is turned about its pivotalconnection in response to expansion of the bellows.

WILLIAM D. COCKRELL.

